Preparation

For the custard:

Heat the oven to 325°F. Heat the cream and milk in a medium saucepan over medium heat until scalded (you’ll see small bubbles on the sides of the pan). Split the vanilla bean in half, if using, and scrape the seeds into the cream. Meanwhile, in a medium bowl, slowly whisk 1/2 cup of the sugar into the egg yolks and eggs. Slowly whisk the hot cream/milk into the sugar/yolk mixture. Strain the mixture through a fine sieve into a pitcher or measuring cup. Stir in the salt and vanilla extract, if using.

For the caramel:

Arrange six 6-oz. ramekins in a baking dish with deep sides and set aside. Put remaining 1/2 cup sugar in a clean saucepan. Carefully add just enough water to dissolve the sugar, and set the pot over high heat.

After a few minutes, the mixture will come to a furious boil; several minutes later, as more water evaporates, it will boil more viscously, and finally it will start to color. Swirl the pan around to even out the caramelization. Once the sugar has started to caramelize, watch it carefully. It takes just seconds for caramel to go from great to burnt.
The mixture will come to a furious boil.

When the caramel is an even dark brown, carefully pour it into the ramekins. Caramel at this stage is over 300°F, so be extremely careful when handling it. Divide it evenly so that each ramekin is covered with a thin layer of dark brown caramel.

Each ramekin is covered with a thin layer of dark brown caramel.

To bake:

Pour the custard into the caramel-lined ramekins, fill the baking dish with water to come halfway up the sides of the ramekins and cover the dish with foil. Bake until just set, 25 to 50 minutes. Remember to start checking early; baking time will depend on the thickness and depth of your ramekins and baking dish. Carefully remove the baking dish from the oven and let the ramekins cool in the water bath. Remove, cover with plastic wrap and refrigerate at least 2 hours or up to 2 days.

Run a thin knife around the edge of the custard and invert onto a dessert plate, scraping any caramel from the ramekin onto the custard.

Espresso custard Omit the vanilla. Crush 1/2 cup espresso beans into coarse pieces, add to the cream/milk, and heat to a simmer. Remove from the heat; infuse for 5 minutes. Strain and proceed.

Ginger custard Omit the vanilla. Cut a 3-inch piece of fresh ginger into very thin slices, add to the cream/milk, and heat to a simmer. Remove from the heat; infuse for 15 to 20 minutes. Strain, bring back to a simmer, and proceed.